Golf balls must meet certain standards in order to be included on the official Conforming Golf Balls List (the “List”) produced by the United States Golf Association and The Royal and Ancient Golf Club of St. Andrews, Scotland, the two ruling bodies for the game of golf. Inclusion on the List is a requirement for use in competitive golf, and most serious players, including recreational golfers, won't use a ball unless it appears on the List.
One of the standards, commonly referred to as the “Symmetry Rule,” specifies that a ball must fly essentially the same distance and for essentially the same amount of time regardless of how it is oriented when struck by the golf club. Thus, golf ball manufacturers generally pursue dimple patterns that provide a ball with symmetrical aerodynamic properties regardless of orientation. In dimple patterns resulting in conforming aerodynamic properties, the dimples on one side of the mold parting line typically have the same design features (i.e., dimple diameter, plan shape, profile shape, edge angle, placement of the dimple within the overall pattern, etc.) as the dimples on the other side of the mold parting line. However, dimple patterns resulting in conforming aerodynamic properties have also been disclosed wherein at least some of the dimples on one side of the mold parting line have a different design feature than those on the other side of the mold parting line. For example, U.S. patent application Ser. No. 14/985,743 to Madson, et al., filed on Dec. 31, 2015, discloses dimple patterns that achieve flight symmetry despite the use of different dimple geometries on the opposing hemispheres due to equivalent dimple volume ratio between opposing hemispheres.
In spite of the Symmetry Rule, golf balls having non-conforming aerodynamic properties have been disclosed and are commercially available. The primary objective of such balls is typically to reduce the effect of hits by unskilled golfers (e.g., hooks and slices) in order for the ball to fly more consistently along a straighter path. For example, the Polara ball, further described in U.S. Pat. No. 3,819,190 to Nepela et al., is a non-conforming ball that allegedly corrects any natural slice or hook through the use of enlarged, shallower dimples along the y-axis and smaller, deeper dimples along the x-axis. Golf balls having non-conforming aerodynamic properties have also been disclosed, for example, in U.S. Patent Application Publication No. 2013/0090189 to Felker et al., which is directed to a non-conforming golf ball having a dimple pattern which causes the ball to have a preferred spin axis because of the weight differences caused by locating different volume dimples in different areas across the ball. This, in turn, allegedly reduces the tendency for the ball to hook or slice during flight.
In contrast to the above golf balls, an object of the present invention is to provide a golf ball with a non-straight flight trajectory when the ball is hit in a particular orientation with respect to the dimple pattern. The non-straight flight trajectory is, at least in part, the result of a novel dimple pattern wherein the dimples on the outer surface of one side of the ball have at least one design feature that is different from the dimples on the outer surface of the other side of the ball.